Metal can, and method for manufacturing metal can and lid-equipped metal can

Abstract

A metal can (10) is joined to a lid (30) by seaming. The metal can (10) comprises a cylindrical circumferential wall (11) and a flange (12). The circumferential wall (11) includes: a first lateral wall (111, 111a, 111b); and a second lateral wall (112, 112a, 112b) connected to the first lateral wall (111, 111a, 111b) with a corner section (113) disposed therebetween. The flange includes a first straight section (121, 121a, 121b), a second straight section (122, 122a, 122b), and a flange corner section (123). The width (W3) of the flange in the flange corner section (123) is less than the width (W1, W2) of the flange in the straight sections (121, 121a, 121b, 122, 122a, 122b).

Description

Metal can, and method for manufacturing metal can and metal can with lid

[0001] The present disclosure relates to a metal can, and more particularly to a metal can joined to a lid by seaming. The present disclosure also relates to a metal can and a method for manufacturing a metal can with a lid.

[0002] For example, large batteries for vehicle or stationary use employ a rectangular metal can as a battery case. This metal can has a rectangular cylindrical peripheral wall and an opening at at least one end in the axial direction. The opening of the metal can is usually closed by a lid.

[0003] The lid is joined to the metal can by, for example, seaming. Patent Document 1 discloses a sealed battery in which a metal can serving as a battery case and a lid are joined by double seaming. In Patent Document 1, the lid and the metal can are overlapped so that a curled portion on the outer periphery of the lid wraps around a flange on the periphery of the opening of the metal can, and then the two are crimped together using a roll or the like to join the metal can and the lid. As a result of this joining, the flange of the metal can becomes a folded portion folded back on the outside of the metal can, and the lid has a folded portion folded back so as to sandwich the folded portion of the metal can from inside and outside. In Patent Document 1, in the double seaming portion, the gap between the tip of the folded portion of the metal can and the folded portion of the lid, and the gap between the tip of the folded portion of the lid and the folded portion of the metal can are each sealed with a sealant.

[0004] Patent Document 2 also discloses a sealed battery in which a metal can serving as a battery case and a lid are joined by double seaming. In Patent Document 2, the metal can before double seaming includes a peripheral wall and a flange (joint) protruding from the peripheral wall toward the outer periphery. Meanwhile, the lid before double seaming includes a lid body, a side wall continuous with the lid body, and a flange (joint) continuous with the side wall. When joining the metal can and the lid, the lid is positioned to seal the opening of the metal can. At this time, the flange on the lid side, together with the side wall, surrounds the flange on the metal can side in a U-shape in cross section. In this state, the flange on the lid side is bent, and the flange on the metal can is sandwiched between the flange on the lid side. Next, a mold is used to bend both the flange on the lid side and the flange on the metal can side. More specifically, a first mold is placed in contact with the main body and side wall of the lid, and a second mold is used to bend the flange on the metal can side and the flange on the lid side that sandwiches it, and press them against the peripheral wall of the metal can. In Patent Document 2, in the metal can and lid body after joining, the width of the seamed portion (the length in the axial direction of the peripheral wall) is greatest at the corner portion of the peripheral wall of the metal can.

[0005] JP 2009-134986 A JP 2010-55961 A

[0006] In Patent Document 2, when a metal can is joined to a lid by seaming, the entire circumference of the flange of the metal can is simultaneously bent using a mold. Because corner portions of a metal can flange have higher deformation resistance than straight portions, it is presumed that when the entire circumference of the metal can flange is simultaneously bent, the timing of deformation of the corner portions is delayed compared to the timing of deformation of the straight portions. In this case, material may flow from the straight portions to the corner portions, resulting in wrinkles at the corner portions. Particularly when the metal can is made of a relatively hard material such as steel, the delay in deformation at the corner portions of the flange becomes significant, making the corner portions prone to wrinkles. Furthermore, even when the flange of the metal can is sequentially bent along the circumferential direction using, for example, a roll, as in Patent Document 1, excess material is likely to occur at the corner portions, potentially resulting in wrinkles. If wrinkles occur at the seam between the metal can and the lid, the sealing performance between the metal can and the lid is reduced.

[0007] An object of the present disclosure is to provide a metal can that can suppress the occurrence of wrinkles at the flange corners when the metal can is joined to a lid by seaming.

[0008] A metal can according to the present disclosure is joined to a lid by seaming. The metal can includes a cylindrical peripheral wall and a flange. The peripheral wall includes a flat first side wall and a flat second side wall connected to the first side wall via a corner portion. The peripheral wall has an opening at at least one axial end thereof. The flange is continuous with the peripheral wall on the opening side. The flange protrudes from the peripheral wall toward the outer periphery. The flange includes a first straight portion, a second straight portion, and a flange corner portion. The first straight portion corresponds to the first side wall of the peripheral wall. The second straight portion corresponds to the second side wall of the peripheral wall. The flange corner portion corresponds to a corner portion of the peripheral wall. The flange corner portion connects the first straight portion and the second straight portion. The width of the flange at the flange corner portion is smaller than the widths of the flange at the first straight portion and the second straight portion.

[0009] According to the metal can according to the present disclosure, when the metal can is joined to a lid by seaming, the occurrence of wrinkles at the flange corners can be suppressed.

[0010] FIG. 1 is a perspective view of a metal can according to an embodiment. FIG. 2 is a plan view of the metal can shown in FIG. 1. FIG. 3A is a schematic view illustrating a method for manufacturing a metal can according to an embodiment. FIG. 3B is a schematic view illustrating a method for manufacturing a metal can according to an embodiment. FIG. 3C is a schematic view illustrating a method for manufacturing a metal can according to an embodiment. FIG. 3D is a schematic view illustrating a method for manufacturing a metal can according to an embodiment. FIG. 4A is a schematic view illustrating a method for manufacturing a metal can with a lid according to an embodiment. FIG. 4B is a schematic view illustrating a method for manufacturing a metal can with a lid according to an embodiment. FIG. 4C is a schematic view illustrating a method for manufacturing a metal can with a lid according to an embodiment. FIG. 4D is a schematic view illustrating a method for manufacturing a metal can with a lid according to an embodiment. FIG. 5 is a schematic view illustrating the relationship between the area per unit length of a flange between a flange corner portion and a straight portion in a seaming metal can. FIG. 6 is a plan view of a metal can according to a modified example of the embodiment. FIG. 7 is a plan view of a metal can according to another modified example of the embodiment. FIG. 8 is a plan view of a metal can according to yet another modified example of the embodiment. FIG. 9 is a plan view of a metal can according to yet another modification of the above embodiment.

[0011] A metal can according to an embodiment is joined to a lid by seaming. The metal can includes a cylindrical peripheral wall and a flange. The peripheral wall includes a flat first side wall and a flat second side wall connected to the first side wall via a corner portion. The peripheral wall has an opening at at least one axial end. The flange is continuous with the peripheral wall on the opening side. The flange protrudes from the peripheral wall to the outer periphery. The flange includes a first straight portion, a second straight portion, and a flange corner portion. The first straight portion corresponds to the first side wall of the peripheral wall. The second straight portion corresponds to the second side wall of the peripheral wall. The flange corner portion corresponds to a corner portion of the peripheral wall. The flange corner portion connects the first straight portion and the second straight portion. The width of the flange at the flange corner portion is smaller than the widths of the flange at the first straight portion and the second straight portion (first configuration).

[0012] In metal cans for seaming, the flange width is generally substantially equal at the flange corner portion and the straight portion. At the flange corner portion, the line length of the outer peripheral edge is greater than that of the inner peripheral edge. On the other hand, at the straight portion, the line length of the outer peripheral edge is equal to that of the inner peripheral edge. Therefore, if the length of the inner peripheral edge of the flange corner portion is taken as unit length, the flange area per unit length is larger at the flange corner portion than at the straight portion. When such a metal can is joined to a lid by seaming, excess material is likely to occur at the flange corner portion, making wrinkles more likely to occur. Furthermore, the excess material may cause the length of the seamed portion in the axial direction of the peripheral wall of the metal can to be greater at the flange corner portion than at the straight portion.

[0013] In contrast, in the metal can according to the first configuration, the width of the flange at the flange corner portion is smaller than the width of the flange at the straight portion. This reduces the area of ​​the flange corner portion compared to when the width of the flange at the flange corner portion is substantially equal to the width of the flange at the straight portion, allowing for a reduction in the amount of material required at the flange corner portion. Therefore, when the metal can is joined to the lid by seaming, excess material is less likely to occur at the flange corner portion. This makes it possible to suppress the occurrence of wrinkles at the flange corner portion.

[0014] In the metal can according to the first configuration, the width of the flange at the flange corner portion is smaller than the width of the flange at the straight portion, so that there is less material at the flange corner portion before seaming. Therefore, when the metal can is joined to the lid by seaming, excess material is less likely to occur at the flange corner portion. In this case, the length of the seamed portion formed by the flange of the metal can and the lid is less likely to be large at the corner portion of the peripheral wall, and the length of the seamed portion can be made uniform between the corner portion and the first and second side walls.

[0015] In the metal can according to the first configuration, when the metal can is viewed in the axial direction, it is preferable that L2 / L1≦1.55, where L1 is the line length of the inner peripheral edge of the flange corner portion and L2 is the line length of the outer peripheral edge of the flange corner portion (second configuration).

[0016] In the second configuration, the line length L2 of the outer peripheral edge of the flange corner is set to 1.55 times or less the line length L1 of the inner peripheral edge, which makes it more difficult for excess material to occur at the flange corner when the metal can is joined to the lid by seaming, and thus makes it easier to prevent wrinkles from occurring at the flange corner.

[0017] In the metal can according to the first or second configuration, the flange may have a thickness of 0.1 mm or more and 0.5 mm or less at the flange corner portion (third configuration).

[0018] The metal can according to any one of the first to third configurations may be made of steel (fourth configuration).

[0019] A manufacturing method according to an embodiment is a method for manufacturing a metal can according to any one of the first to fourth configurations. The method for manufacturing a metal can includes the steps of preparing a cylindrical raw can having an opening at at least one axial end, and forming a flange by bending a portion of the raw can outward on the opening side of the raw can. After the forming step, the flange has a width at the flange corner that is smaller than the first straight portion and the second straight portion (fifth configuration).

[0020] A manufacturing method according to the embodiment is a method for manufacturing a metal can with a lid, which includes the steps of preparing a metal can according to any one of the first to fourth configurations and a lid, and joining the lid to a flange by seaming and sealing the opening with the lid (sixth configuration).

[0021] In the manufacturing method according to the sixth aspect, the metal can may be a battery case (seventh aspect).

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In these drawings, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0023] [Configuration of Metal Can] Fig. 1 is a perspective view of a metal can 10 according to this embodiment. Referring to Fig. 1, the metal can 10 includes a peripheral wall 11 and a flange 12. In this embodiment, the metal can 10 further includes a bottom plate 13.

[0024] The peripheral wall 11 has a cylindrical shape. The peripheral wall 11 typically has a rectangular cylindrical shape. The peripheral wall 11 includes first side walls 111 a and 111 b and second side walls 112 a and 112 b. The peripheral wall 11 further includes four corner portions 113.

[0025] The first side walls 111a, 111b have a flat plate shape. In this embodiment, each of the first side walls 111a, 111b has a substantially rectangular flat plate shape. The first side walls 111a, 111b are arranged to face each other. Corner portions 113 are provided continuously on both side edges of the first side wall 111a. Similarly, corner portions 113 are provided continuously on both side edges of the first side wall 111b.

[0026] The second side walls 112a, 112b have a flat plate shape. In this embodiment, each of the second side walls 112a, 112b has a substantially rectangular flat plate shape. The second side walls 112a, 112b are arranged to face each other. The second side walls 112a, 112b face each other in a direction intersecting the facing direction of the first side walls 111a, 111b. For example, when viewed along the axial direction of the peripheral wall 11, the first side walls 111a, 111b may face each other in the short direction of the rectangular cylindrical peripheral wall 11, and the second side walls 112a, 112b may face each other in the long direction of the peripheral wall 11. Alternatively, when viewed along the axial direction of the peripheral wall 11, the first side walls 111a, 111b may face each other in the long direction of the rectangular cylindrical peripheral wall 11, and the second side walls 112a, 112b may face each other in the short direction of the peripheral wall 11.

[0027] The second side walls 112a and 112b are connected to the first side walls 111a and 111b, respectively, via corner portions 113. The second side wall 112a is connected to the first side wall 111a via one of the corner portions 113 and is connected to the first side wall 111b via the other corner portion 113. The second side wall 112b is connected to the first side wall 111a via one of the corner portions 113 on the opposite side of the second side wall 112a and is connected to the first side wall 111b via the other corner portion 113.

[0028] The peripheral wall 11 has an opening 114 at at least one axial end. In this embodiment, the peripheral wall 11 has the opening 114 at one axial end and the bottom plate 13 at the other axial end.

[0029] The flange 12 is continuous with the peripheral wall 11 on the opening 114 side. The flange 12 protrudes from the peripheral wall 11 toward the outer periphery of the peripheral wall 11. The flange 12 corresponds to the rectangular cylindrical peripheral wall 11 and may have a rectangular frame shape when viewed along the axial direction of the peripheral wall 11. The flange 12 includes first straight portions 121a, 121b and second straight portions 122a, 122b. The flange 12 further includes four flange corner portions 123.

[0030] The first straight portions 121a, 121b are portions of the flange 12 that correspond to the first side walls 111a, 111b of the peripheral wall 11, respectively. One first straight portion 121a is continuous with one first side wall 111a of the peripheral wall 11 and extends along the first side wall 111a. The first straight portion 121a is substantially straight when viewed along the axial direction of the peripheral wall 11. The other first straight portion 121b is continuous with the other first side wall 111b of the peripheral wall 11 and extends along the first side wall 111b. The first straight portion 121b is substantially straight when viewed along the axial direction of the peripheral wall 11.

[0031] The second straight portions 122a, 122b are portions of the flange 12 that correspond to the second side walls 112a, 112b of the peripheral wall 11, respectively. One second straight portion 122a is continuous with one second side wall 112a of the peripheral wall 11 and extends along the second side wall 112a. The second straight portion 122a is substantially straight when viewed along the axial direction of the peripheral wall 11. The other second straight portion 122b is continuous with the other second side wall 112b of the peripheral wall 11 and extends along the second side wall 112b. The second straight portion 122b is substantially straight when viewed along the axial direction of the peripheral wall 11.

[0032] The flange corner portions 123 are portions of the flange 12 that correspond to the corner portions 113 of the peripheral wall 11. Each of the flange corner portions 123 connects the first straight portion 121a or 121b to the second straight portion 122a or 122b.

[0033] Fig. 2 is a view (plan view) of the metal can 10 as viewed from the flange 12 side along the axial direction of the peripheral wall 11. Fig. 2 shows an enlarged view of one of the flange corner portions 123 and its vicinity. Hereinafter, the first side walls 111a and 111b of the peripheral wall 11 will be collectively referred to as the first side wall 111 unless there is a need to distinguish them, and the second side walls 112a and 112b will be collectively referred to as the second side wall 112 unless there is a need to distinguish them. Similarly, the first straight portions 121a and 121b of the flange 12 will be collectively referred to as the first straight portion 121 unless there is a need to distinguish them, and the second straight portions 122a and 122b will be collectively referred to as the second straight portion 122 unless there is a need to distinguish them.

[0034] Referring to FIG. 2, the first straight portion 121 is ｉｎ and the outer peripheral edge E1 ｏｕｔ The second straight portion 122 has an inner peripheral edge E2 ｉｎ and the outer periphery E2 ｏｕｔ The flange corner portion 123 has an inner peripheral edge E3 ｉｎ and the outer edge E3 ｏｕｔ and

[0035] Inner periphery E1 ｉｎ , E2 ｉｎ , E3 ｉｎ is located on the boundary between the peripheral wall 11 and the flange 12. ｉｎ , E2 ｉｎ The inner peripheral edge E3 of the flange corner portion 123 has a linear shape in a plan view of the metal can 10. ｉｎ is the inner peripheral edge E1 of the first straight portion 121 ｉｎ and the inner peripheral edge E2 of the second straight portion 122 ｉｎ and an inner peripheral edge E1 ｉｎ , E2 ｉｎ Connect the

[0036] Outer edge E1 ｏｕｔ , E2 ｏｕｔ , E3 ｏｕｔ are located on the free edge of the flange 12, and the inner peripheral edge E1 ｉｎ , E2 ｉｎ , E3 ｉｎ The straight portions 121 and 122 are arranged on the outer side of the outer peripheral edge E1 ｏｕｔ , E2ｏｕｔ The outer peripheral edge E3 of the flange corner portion 123 has a linear shape in a plan view of the metal can 10. ｏｕｔ is the outer peripheral edge E1 of the first straight portion 121 ｏｕｔ and the outer peripheral edge E2 of the second straight portion 122 ｏｕｔ and an outer peripheral edge E1 ｏｕｔ , E2 ｏｕｔ Connect the

[0037] The flange 12 has a width W1 at the first straight portion 121. The width W1 is the width between the inner peripheral edge E1 of the first straight portion 121 and the inner peripheral edge E1 of the first straight portion 121. ｉｎ From the outer edge E1 ｏｕｔ The flange 12 may have a substantially constant width W1 throughout the first straight portion 121.

[0038] The flange 12 has a width W2 at the second straight portion 122. The width W2 is the width of the inner peripheral edge E2 of the second straight portion 122. ｉｎ From the outer edge E2 ｏｕｔ The flange 12 may have a substantially constant width W2 throughout the entire second straight portion 122. The width W2 of the flange 12 at the second straight portion 122 may be substantially equal to the width W1 of the flange 12 at the first straight portion 121. The widths W1 and W2 of the flange 12 at the positions of the straight portions 121 and 122 are, for example, 1.0 mm or more, and preferably 1.5 mm or more. The widths W1 and W2 are, for example, 4.5 mm or less, and preferably 4.0 mm or less.

[0039] At the flange corner portion 123, the width of the flange 12 is equal to or smaller than the widths W1 and W2 at the straight portions 121 and 122 throughout the flange corner portion 123. The flange 12 has a width W3 that is smaller than the widths W1 and W2 at at least a portion of the flange corner portion 123. The width W3 is determined by the inner peripheral edge E3 of the flange corner portion 123. ｉｎ From outer edge E3 ｏｕｔ In the example of FIG. 2, the flange 12 is ｉｎThe flange 12 has a minimum width W3 at the flange corner portion 123 at the center in the extension direction. The width W3 of the flange 12 at the flange corner portion 123 is, for example, 1.0 mm or more, and preferably 1.5 mm or more. The width W3 is, for example, 4.0 mm or less, and preferably 3.5 mm or less. The width W3 is smaller than the widths W1 and W2 by, for example, 0.1 mm or more, and preferably 0.3 mm or more.

[0040] When the metal can 10 is viewed from the flange 12 side along the axial direction of the peripheral wall 11, i.e., when viewed from the plan view of the metal can 10, an imaginary arc A having a center of curvature C at the intersection of the lines S1 and S2 is shown by a two-dot chain line in Fig. 2. The line S1 is an imaginary line that crosses the flange 12 at the boundary between the first straight portion 121 and the flange corner portion 123 when viewed from the plan view of the metal can 10. The line S1 is an imaginary line that crosses the flange 12 at the boundary between the first straight portion 121 and the flange corner portion 123 when viewed from the plan view of the metal can 10. ｉｎ and outer periphery E1 ｏｕｔ The line S2 passes through the end point of the flange corner portion 123 of the second straight portion 122. The line S2 is an imaginary line that crosses the flange 12 at the boundary between the second straight portion 122 and the flange corner portion 123 in a plan view of the metal can 10. The line S2 passes through the end point of the flange corner portion 123 of the second straight portion 122 in a plan view of the metal can 10. ｉｎ and outer edge E2 ｏｕｔ The arc A passes through the end point of the flange corner portion 123 of the first straight portion 121. ｏｕｔ from the end point of the flange corner portion 123 side to the outer peripheral edge E2 of the second straight portion 122 ｏｕｔ The straight portions 121 and 122 extend to the end point of the flange corner portion 123. ｏｕｔ , E2 ｏｕｔ are tangents at both ends of the arc A. The central angle θ of the arc A may be, for example, 90°.

[0041] In a plan view of the metal can 10, the outer peripheral edge E3 of the flange corner portion 123 ｏｕｔ At least a portion of the outer peripheral edge E3 is disposed inside the arc A. ｏｕｔ Preferably, the entire or most of the outer periphery E3 is disposed inside the arc A in a plan view of the metal can 10. ｏｕｔThe entire inner peripheral edge E3 of the flange corner portion 123 is disposed inside the arc A. ｉｎ is the outer peripheral edge E3 in a plan view of the metal can 10. ｏｕｔ It is located inside the

[0042] In the example of FIG. 2, the inner peripheral edge E3 ｉｎ and outer edge E3 ｏｕｔ The outer peripheral edge E3 has a substantially arcuate shape in a plan view of the metal can 10. ｏｕｔ The radius of curvature of the inner peripheral edge E3 is larger than the radius of curvature of the arc A. ｉｎ The radius of curvature of arc A is smaller than the radius of curvature of arc B.

[0043] In a plan view of the metal can 10, the inner peripheral edge E3 of the flange corner portion 123 ｉｎ has a line length L1 and an outer peripheral edge E3 ｏｕｔ When the line length of the arc A in the plan view of the metal can 10 is the reference line length RL, the outer peripheral edge E3 ｏｕｔ The line length L2 of the inner peripheral edge E3 is typically shorter than the reference line length RL. ｉｎ Line length L1 and outer periphery E1 ｏｕｔ The line length L2 satisfies, for example, L2 / L1≦1.55. The line lengths L1 and L2 preferably satisfy L2 / L1≦1.50, and more preferably satisfy L2 / L1≦1.45.

[0044] Outer periphery E3 of flange corner portion 123 ｏｕｔ The line length L2 is the inner peripheral edge E3 ｉｎ The line lengths L1 and L2 satisfy, for example, 1.15≦L2 / L1. The line lengths L1 and L2 preferably satisfy 1.20≦L2 / L1, and more preferably satisfy 1.23≦L2 / L1.

[0045] [Method for Manufacturing Metal Can] Next, a method for manufacturing the metal can 10 will be described with reference to Figures 3A to 3D. The method for manufacturing the metal can 10 according to this embodiment includes a preparation step and a molding step.

[0046] 3A , in the preparation step, a material can 20 is prepared. The material can 20 has a cylindrical shape. The material can 20 may have a rectangular cylindrical shape. The material can 20 has an opening 21 at at least one end in the axial direction.

[0047] In this embodiment, the material can 20 has a cylindrical shape with a bottom. That is, the material can 20 includes a peripheral wall 22 and a bottom plate 23. The opening 21 is provided at one end of the peripheral wall 22 in the axial direction of the material can 20. The bottom plate 23 is provided at the other end of the peripheral wall 22 in the axial direction of the material can 20.

[0048] The peripheral wall 22 includes first side walls 221 a and 221 b and second side walls 222 a and 222 b. The peripheral wall 22 further includes four corner portions 223.

[0049] The first side walls 221a, 221b have a flat plate shape. In this embodiment, each of the first side walls 221a, 221b has a substantially rectangular flat plate shape. The first side walls 221a, 221b are arranged to face each other. Corner portions 223 are provided continuously on both side edges of the first side wall 221a. Similarly, corner portions 223 are provided continuously on both side edges of the first side wall 221b.

[0050] The second side walls 222a, 222b have a flat plate shape. In this embodiment, each of the second side walls 222a, 222b has a substantially rectangular flat plate shape. The second side walls 222a, 222b are arranged to face each other. The second side walls 222a, 222b face each other in a direction intersecting the facing direction of the first side walls 221a, 221b. For example, when viewed along the axial direction of the peripheral wall 22, the first side walls 221a, 221b may face each other in the short direction of the rectangular cylindrical peripheral wall 22, and the second side walls 222a, 222b may face each other in the long direction of the peripheral wall 22. Alternatively, when viewed along the axial direction of the peripheral wall 22, the first side walls 221a, 221b may face each other in the long direction of the rectangular cylindrical peripheral wall 22, and the second side walls 222a, 222b may face each other in the short direction of the peripheral wall 22.

[0051] The second side walls 222a and 222b are connected to the first side walls 221a and 221b, respectively, via corner portions 223. The second side wall 222a is connected to the first side wall 221a via one of the corner portions 223 and is connected to the first side wall 221b via the other corner portion 223. The second side wall 222b is connected to the first side wall 221a via one of the corner portions 223 on the opposite side of the second side wall 222a and is connected to the first side wall 221b via the other corner portion 223.

[0052] 3A , a recess 224 may be provided in the edge (opening edge) of the peripheral wall 22 on the opening 21 side. The recess 224 is provided in a position corresponding to the corner portion 223 on the opening edge of the peripheral wall 22. The recess 224 has a shape that is recessed in the axial direction relative to the other portions of the opening edge of the peripheral wall 22.

[0053] The material can 20 is formed, for example, by drawing a metal plate (blank). The material can 20 may be formed, for example, by drawing a metal plate multiple times (multi-stage drawing).

[0054] (Forming Step) Referring to FIGS. 3B and 3C, in the forming step, a part of the material can 20 on the opening 21 side of the material can 20 is bent outward to form the flange 12.

[0055] 3B shows a cross section (longitudinal cross section) of the material can 20 before the forming process, cut along its axial direction. As shown in FIG. 3B, in the material can 20 before the forming process, the peripheral wall 22 extends substantially parallel to the axial direction in the longitudinal cross section. This material can 20 is subjected to a bending process using, for example, a known mold (not shown). Specifically, the portion of the peripheral wall 22 on the opening 21 side is bent outward. The bent portion of the peripheral wall 22 becomes the flange 12 as shown in FIGS. 3C and 3D , and the metal can 10 is obtained from the material can 20. The portion of the peripheral wall 22 of the material can 20 that is not bent becomes the peripheral wall 11 of the metal can 10.

[0056] 3C is a partial vertical cross-sectional view of the metal can 10 at the position of the flange corner portion 123. FIG. 3D is a partial vertical cross-sectional view of the metal can 10 at the position of the straight portion 121 or 122 of the flange 12. After the forming process, the flange 12 has a width W3 at the flange corner portion 123 that is smaller than the widths W1 and W2 of the first straight portion 121 and the second straight portion 122. In this embodiment, since the recess 224 is previously provided at the opening edge of the peripheral wall 22 of the material can 20 ( FIG. 3A ), the width W3 of the flange 12 at the flange corner portion 123 is smaller than the widths W1 and W2 of the flange 12 at the straight portions 121 and 122 immediately after the forming process. The recess 224 may be provided at the opening edge of the peripheral wall 22 of the material can 20 in anticipation of obtaining the target width W3 at the flange corner portion 123 when a portion of the material can 20 is bent to form the flange 12. At the flange corner portion 123 after the forming process, the outer peripheral edge E3 ｏｕｔ The line length L2 is shorter than the reference line length RL (FIG. 2).

[0057] However, the forming process may be performed without providing the recess 224 ( FIG. 3A ) on the opening edge of the peripheral wall 22 of the material can 20. For example, after forming the flange 12 by bending a portion of the material can 20 outward, the flange 12 may be partially trimmed at the position of the flange corner portion 123. Even in this case, the flange 12 may have a width W3 at the flange corner portion 123 that is smaller than the widths of the first straight portion 121 and the second straight portion 122 after the forming process. Trimming of the flange corner portion 123 may be performed before or after the flange 12 forming process.

[0058] The flange 12 may have a thickness t of 0.1 mm or more and 0.5 mm or less at the flange corner portion 123. The thickness t may be, for example, ｏｕｔ From inner edge E3 ｉｎThe thickness t of the flange 12 at the flange corner portion 123 may be the same as or different from the thickness of the flange 12 at the straight portions 121 and 122. For example, when the material can 20 ( FIG. 3A ) is formed by drawing, the thickness t of the flange corner portion 123 may be larger than the thickness of the straight portions 121 and 122. The thickness t of the flange 12 may be the same as or different from the thickness of the peripheral wall 11.

[0059] [Method for manufacturing a metal can with a lid] A method for manufacturing a metal can with a lid according to this embodiment will be described with reference to Figures 4A to 4D. The method for manufacturing a metal can with a lid according to this embodiment includes a preparation step and a joining step.

[0060] 4A , in the preparation step, the metal can 10 and the lid 30 are prepared. The metal can 10 may be a battery case. That is, in this embodiment, a metal can with a lid that is a battery may be manufactured. The battery is, for example, a lithium-ion secondary battery.

[0061] The lid body 30 has, for example, a substantially rectangular shape in a plan view. In the example of FIG. 4A , the lid body 30 includes a bottom plate 31, a vertical wall 32, and a flange 33. The vertical wall 32 is provided to surround the bottom plate 31. The vertical wall 32 connects the bottom plate 31 and the flange 33. The flange 33 protrudes from the vertical wall 32 toward its outer periphery. The flange 33 may have, for example, a shape in which its outer periphery 331 is bent relative to its inner periphery 332. However, the configuration of the lid body 30 is not limited to the example shown in FIG. 4A . The lid body 30 may be any known lid body as long as it has a configuration suitable for seaming.

[0062] The metal can 10 and the lid 30 are typically made of steel. This steel may be a stainless steel sheet or a surface-treated steel sheet. Surface-treated steel sheets include plated steel sheets. When the metal can 10 and the lid 30 are a battery case and its lid, the surface-treated steel sheet is preferably a nickel-plated steel sheet. Alternatively, when the metal can 10 and the lid 30 are a battery case and its lid, the steel material forming the metal can 10 and the lid 30 is preferably a stainless steel sheet. However, the metal can 10 and the lid 30 may also be made of a material such as aluminum, titanium, copper, or an alloy thereof.

[0063] 4B to 4D , in the joining step, the lid 30 is joined to the flange 12 of the metal can 10 by seaming, and the opening 114 in the peripheral wall 11 of the metal can 10 is sealed with the lid 30. The metal can 10 is joined to the lid 30 by, for example, double seaming. In the joining step, the metal can 10 and the lid 30 can be joined using a seaming machine 40.

[0064] A general seaming machine can be used as the seaming machine 40. As shown in FIG. 4B , the seaming machine 40 includes, for example, a first seaming roll 41, a second seaming roll 42, a seaming chuck 43, and a lifter 44. When starting the joining process, the metal can 10 with the lid 30 stacked thereon is first placed on the lifter 44. At this time, the metal can 10 contains the necessary contents. For example, if the metal can 10 is a battery case and a metal can with a lid for use as a battery is manufactured, an electrode body, an electrolyte, etc. are contained in the metal can 10.

[0065] After the necessary contents are placed in the metal can 10, the lid 30 is placed on the metal can 10 to close the opening 114. Specifically, the flange 33 of the lid 30 is placed on the flange 12 of the metal can 10, and the vertical wall 32 of the lid 30 faces the peripheral wall 11 inside the metal can 10.

[0066] Next, the metal can 10 and the lid 30 are raised together with the lifter 44, and the metal can 10 and the lid 30 are fixed between the seaming chuck 43 and the lifter 44. Then, as shown in Fig. 4C , a first seaming roll 41 is brought close to the metal can 10 and the lid 30, and the first seaming roll 41 deforms the lid 30 and the metal can 10 so that the lid 30 rolls in the flange 12 of the metal can 10. In this embodiment, the flange 12 of the metal can 10 is bent toward the peripheral wall 11 while being sandwiched between the outer peripheral portion 331 and the inner peripheral portion 332 of the flange 33 of the lid 30.

[0067] 4D , a second seaming roll 42 is brought close to the metal can 10 and the lid 30, and the second seaming roll 42 presses the flange 33 of the lid 30, together with the flange 12 of the metal can 10, toward the peripheral wall 11. This bonds the metal can 10 to the lid 30, producing a metal can with a lid. A sealant may be disposed between the flange 33 of the lid 30 and the flange 12 of the metal can 10 to improve the sealing performance of the metal can with a lid.

[0068] [Effect] Assuming that the width W3 of the flange 12 at the flange corner portion 123 is substantially equal to the widths W1 and W2 of the flange at the straight portions 121 and 122, the inner peripheral edge E3 of the flange corner portion 123 ｉｎ 5, the area of ​​the flange 12 per linear length L1 (unit length) is large at the flange corner portion 123 and small at the straight portions 121, 122, regardless of the radius of curvature of the corner portion 223 of the material can 20. The area of ​​the flange 12 here is the area of ​​the flange 12 in a plan view of the metal can 10, that is, the area of ​​the flange 12 when projected onto a plane perpendicular to the axial direction of the peripheral wall 11.

[0069] On the other hand, in the metal can 10 according to this embodiment, the width W3 of the flange 12 at the flange corner portion 123 is smaller than the widths W1 and W2 of the flange at the straight portions 121 and 122. This allows the area of ​​the flange corner portion 123 to be reduced and approached to the area per unit length of the straight portions 121 and 122, compared to when the width W3 of the flange 12 at the flange corner portion 123 is substantially equal to the widths W1 and W2 of the flange at the straight portions 121 and 122. This allows the amount of material required for the flange corner portion 123 to be reduced.

[0070] By reducing the amount of material in the flange corner portion 123 in advance, excess material is less likely to occur in the flange corner portion 123 when the metal can 10 is joined to the lid 30 by seaming. This prevents wrinkles from occurring in the flange corner portion 123, improving the sealing performance of the metal can with a lid. Furthermore, the axial length of the peripheral wall 11 of the seamed portion formed by the flange 12 of the metal can 10 and the lid 30 is less likely to increase at the corner portion 113, making it possible to uniform the axial length of the seamed portion throughout the metal can with a lid.

[0071] In the metal can 10 according to this embodiment, the inner peripheral edge E3 of the flange corner portion 123 ｉｎ Line length L1 and outer edge E3 ｏｕｔ The line length L2 preferably satisfies L2 / L1≦1.55. The line lengths L1 and L2 more preferably satisfy L2 / L1≦1.45. By appropriately setting L2 / L1, excess material is less likely to occur at the flange corner portion 123 when the metal can 10 is joined to the lid 30 by seaming. Therefore, the occurrence of wrinkles at the flange corner portion 123 is more likely to be suppressed.

[0072] When the thickness t of the flange 12 of the metal can 10 is small, the flange 12 has low resistance to wrinkles, and therefore wrinkles are likely to occur particularly at the flange corners 123 when the metal can 10 is joined to the lid 30 by seaming. However, in this embodiment, excess material is less likely to occur at the flange corners 123, so that wrinkles can be suppressed at the flange corners 123 even when the thickness t of the flange 12 is relatively small. In the metal can 10 according to this embodiment, the flange 12 can have a thickness t of 0.1 mm or more and 0.5 mm or less at the position of the flange corners 123.

[0073] The metal can 10 according to the present embodiment may be formed from a steel material. Steel has higher rigidity than aluminum alloy materials and the like. Therefore, by forming the metal can 10 from a steel material, the metal can 10 can be made thinner while maintaining its rigidity. As a result, for example, when a plurality of batteries using the metal cans 10 as battery cases are arranged, the proportion of the mounting space occupied by the metal cans 10 can be reduced. Therefore, the space efficiency and energy density of the battery can be improved.

[0074] The metal can 10 can be manufactured from a material can 20. For example, if the material can 20 is a drawn product, each corner 223 of the peripheral wall 22 is subjected to shrinkage deformation during the drawing process. As a result, the corners 223 have a lower formability than the side walls 221a, 221b, 222a, and 222b. When such a material can 20 is bent to form the flange 12, elongation deformation occurs at the opening edge of the material can 20 at the corners 223, increasing the load and making it more likely to crack. On the other hand, in this embodiment, a recess 224 is formed at the opening edge of the material can 20. In this case, the line length of the opening edge of the material can 20 at the corners 223 is shortened, thereby reducing the load on the opening edge when forming the flange 12. Therefore, cracks are less likely to occur at the corners 223.

[0075] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0076] In the metal can 10 according to the above embodiment, in plan view, the outer peripheral edge E3 of the flange corner portion 123 ｏｕｔ However, the outer peripheral edge E3 has an arc shape with a constant radius of curvature. ｏｕｔ 6 and 7, when viewed from above, the outer peripheral edge E3 of the flange corner portion 123 of the metal can 10 may be formed as follows. ｏｕｔ Alternatively, the outer peripheral edge E3 of the flange corner portion 123 may have a curved shape whose radius of curvature changes along the extending direction. ｏｕｔ The inner peripheral edge E3 may include a linear portion as shown in FIG. 8, or may include an inner peripheral edge E4 as shown in FIG. ｉｎ The side may include a recessed portion.

[0077] In the above embodiment, the metal can 10 has a cylindrical shape with a bottom. That is, the metal can 10 has an opening 114 at one end of the peripheral wall 11 and a bottom plate 13 at the other end of the peripheral wall 11. However, the metal can 10 may have a cylindrical shape without a bottom. In this case, the peripheral wall 11 of the metal can 10 has openings 114 at both axial ends. The metal can 10 may be joined to the lid 30 by seaming on the side of both openings 114. Alternatively, the metal can 10 may be joined to the lid 30 by seaming on one side of both openings 114, and joined to another lid on the other side by a joining method other than seaming.

[0078] Similarly, the material can 20 before being made into the metal can 10 may be a cylindrical shape with a bottom as in the above embodiment, or may be a cylindrical shape without a bottom. When the material can 20 is a cylindrical shape without a bottom, for example, the material can 20 may be formed by bending a metal plate (blank) multiple times and then welding the ends of the metal plate together. Alternatively, the material can 20 may be formed by correcting a circular tube into a rectangular tube.

[0079] In the above embodiment, the metal can 10 is joined to the lid 30 using a seaming machine 40. However, the metal can 10 may also be joined to the lid 30 by seaming using a mold, such as that described in Patent Document 2. In this case, the entire circumference of the flange 12 of the metal can 10 is simultaneously bent, which tends to cause so-called shrink flange forming at the flange corner portion 123, resulting in increased thickness. If the metal can 10 is made of a relatively hard material, such as steel, the timing of deformation at the flange corner portion 123 tends to lag behind that at the straight portions 121 and 122, resulting in particularly significant increased thickness at the flange corner portion 123. However, in the metal can 10 according to the above embodiment, the width W3 at the flange corner portion 123 is smaller than that of the straight portions 121 and 122, thereby reducing the amount of material in advance, thereby suppressing the occurrence of wrinkles.

[0080] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to the following examples.

[0081] In order to confirm the effects of the present disclosure, a CAE analysis was carried out using general-purpose analysis software (LS-DYNA, manufactured by JSOL Corporation). The conditions of the metal can for seaming used in this analysis are as follows: Material: Nickel-plated steel sheet Thickness: 0.3 mm Shape of the metal can: Bottomless rectangular cylinder Dimensions of the peripheral wall: Depth (length in the short direction) 26.5 mm x Width (length in the long direction) 148.0 mm x Height (length in the axial direction) 100.0 mm Radius of curvature of the corner of the peripheral wall (inner circumference): 10 mm Width of the straight part of the flange: 2.5 mm Shape of the flange corner: Figure 2

[0082] In this analysis, the ratio of the line length L2 of the outer edge to the line length L1 of the inner edge of the flange corner (L2 / L1) was changed to investigate the effect of L2 / L1 on wrinkles that occur at the flange corner due to seaming. The L2 / L1 conditions and analysis results are shown in Table 1.

[0083]

[0084] In this analysis, cases where no wrinkles occurred at the flange corner after seaming were evaluated as ◯ (good), cases where seaming was completed despite small wrinkles occurring were evaluated as △ (passable), and cases where seaming was not possible due to the occurrence of wrinkles were evaluated as × (unacceptable).

[0085] In Table 1, the comparative example where L2 / L1 = 1.60 is a case where the flange width at the flange corner portion is equal to the flange width at the straight portion, while Examples 1 to 7 where L2 / L1 ≦ 1.55 are cases where the flange width at the flange corner portion is smaller than the flange width at the straight portion.

[0086] As shown in Table 1, in the comparative example, wrinkles occurred at the flange corners, making it impossible to join the flange of the metal can and the lid by seaming, and the wrinkle evaluation was poor. On the other hand, in Examples 1 to 7, no wrinkles occurred at the flange corners, or even if wrinkles occurred, only a few wrinkles occurred, and the flange of the metal can and the lid could be joined by seaming. This analysis confirmed that by making the width of the flange at the flange corners smaller than the width of the flange at the straight portion, the occurrence of wrinkles at the flange corners can be suppressed when joining the metal can and the lid by seaming.

[0087] In Example 4 where L2 / L1 = 1.50 and Example 7 where L2 / L1 = 1.55, seaming was possible, but small wrinkles occurred at the flange corners of the seamed metal cans. However, in Examples 1 to 3 and 5 to 6 where L2 / L1 ≦ 1.45, no wrinkles occurred at the flange corners of the seamed metal cans. From these results, it can be said that in order to make it more difficult for wrinkles to occur at the flange corners, it is preferable to set L2 / L1 ≦ 1.45.

[0088] 10: Metal can 11: Peripheral wall 111, 111a, 111b: First side wall 112, 112a, 112b: Second side wall 113: Corner portion 114: Opening 12: Flange 121, 121a, 121b: First straight portion 122, 122a, 122b: Second straight portion 123: Flange corner portion 20: Material can 21: Opening 30: Lid

Claims

1. A metal can joined to a lid by seaming, comprising: a cylindrical peripheral wall including a flat first side wall and a flat second side wall connected to the first side wall via a corner portion, the peripheral wall having an opening at at least one axial end; and a flange continuing to the peripheral wall on the opening side and projecting outward from the peripheral wall, wherein the flange includes a first straight portion corresponding to the first side wall, a second straight portion corresponding to the second side wall, and a flange corner portion corresponding to the corner portion and connecting the first straight portion and the second straight portion, and the width of the flange at the flange corner portion is smaller than the width of the flange at the first straight portion and the second straight portion.

2. A metal can according to claim 1, wherein, when the metal can is viewed along the axial direction, the line length of the inner peripheral edge of the flange corner portion is L1 and the line length of the outer peripheral edge of the flange corner portion is L2, and L2 / L1 is ≦1.

55.

3. A metal can according to claim 1, wherein the flange has a thickness of 0.1 mm or more and 0.5 mm or less at the flange corner portion.

4. A metal can according to claim 1, wherein said metal can is made of steel.

5. A method for manufacturing metal cans as claimed in any one of claims 1 to 4, comprising the steps of: preparing a cylindrical material can having an opening at at least one end in the axial direction; and forming the flange by bending a portion of the material can outward on the opening side of the material can, wherein after the forming step, the flange has a width at the flange corner that is smaller than the widths of the first straight portion and the second straight portion.

6. A method for manufacturing a metal can with a lid, comprising the steps of: preparing a metal can according to any one of claims 1 to 4 and a lid; and joining the lid to the flange by seaming, and sealing the opening with the lid.

7. The manufacturing method according to claim 6, wherein the metal can is a battery case.

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